Mechanical stoker



March 19, 1929. J, 5. s. FULTON MECHANICAL STOKER 1925 3 Sheets-Sheet 1 Filed Oct. 12,

INVENTOR.

fomv 5. 5. FDA 70M ATTORNEYS,

Mairch 19, 1929.

Filed Oct. 12, 1925 PI.Z

J. S. S. FULTON MECHANICAL STOKER 5 Sheets-Sheet 2 INVENTOR. J'o/m/ 0'. .5. F244 TOM A TTORNEYJ.

March 19, 1929. 5, FULTON I Q 1,706,287

MECHANICAL STOKER Filed Oct. 12, 1925 3 Sheets-Sheet 3 NVEN TOR. Jbmv 5. .5. F01 TOM li/MW ATTORNEYJ,

Patented Mar. 1 9, 1929.

UNITED STATES JOHN S. S. FULTON, OF MARION, INDIANA.

MECHANICAL STOKER.

Application filed October 12, 1925. Serial No. 61,899.

This invention pertains primarily to a mechanical actuating and timing mechanism for operating stoker grates for furnaces and the like. The main object of the invention 1s the provision of mechanism which may beelnployed for a number of purposeswherein 1t is desired to periodically and at timed intervals operate a device such as to turn and advance billets in a heating furnace, etc.

Another object of this invention is to provide a mechanism of this character particularly applicable to actuating stoking grates wherein a constantly operating motor will be caused to actuate the stoker grates at predetermined intervals and after actuating them return'them to normal position within a given limit of time. This not only serves .to project the stoking grates upwardly into stoking position, but promptly returns them to normal position so that they remaln in stoking position for a very short period of time and not be destroyed or seriously affected by the action of the fire.

Another feature of the invention resides in the principle involved for accomplishing'the above, and the particular mechanism' for actuating and returning the stokers wherein such mechanism may be economically constructed and installed as Will be hereinafter more fully set forth and described.

The full nature of theinvention Will be understood from the accompanying drawings and the following description and claims.

Fig. 1 is a front elevation of a furnace showing the mechanism mounted thereon. Fig. 2 is a section taken on the line 2-2 of Fig. 1. Fig. 3 is a central longitudinal section through one set of actuating and timing members. Figure. 4 is a section on line 14 of Fig. 3. I

In the drawings there is shown the front portion of a"-' furnace structure including stoker side frames 10, a fire door 11, and stoker grates 12. In the course of normal operation, each set of stok-ing grates requires advancing on an average of about every 18 minutes,-,

whereby the fuel is pushed toward the rear of the grate as is well understood in stoking grates of this character. By advancing is understood to be aifull normal movement. of each Set of stoking grates from normal fuel supporting position to stoking position and back again to fuel supporting position. The mechanism herein described is assumed, for illustrating purpose, to stoke every 18 'minutes, it being understood that there is a Wide range of time between stoking intervals which is determined by the operator at will in accordance with the quality and kind of fuel, the rate of combustion, the length of the stoker, etc. When a set of stoker grates is advanced, they are projected up into the burn ing bed of fuel and in consequence can only be, allowed to remain there a very short period of time or the action of the-fire will destroy them. Actual experience has demonstrated that this period should not exceed a minute at any one time.

Heretofore there have been mechanical stokers of this character and of similar construction adapted to project the stoker grates into the fire, but the mechanism for operating them, permitted themwhen advanced, to remain exposed to' the action of the fire so long that they were soon destroyed, and if the mechanism were set to return the stoking grates in suflicient time to prevent burnin the grates would be prematurely advance and the whole structure rendered inoperative or rather of no practical value. In this structure-the grates are promptly brought back from their projecting positions within a per1od of not exceeding thirty seconds, while they will not be again advanced into the fire for a predetermined period, or about 18 minutes. This period of projection may be varied as will hereinafter more fully appean.

Mounted on one side of one of the stoker side frames 10 there is a motor which is herein shown in the form of a cylinder le in which the connecting rod 14: is actuated in the usual manner. Said connecting rod is pivoted to a crank arm 15 which in turn is provided with a collar 16 keyed to the drive shaft 17. The shaft 17 extends across the exterior front of the furnace as shown in Figs. 1 and 2.

The shaft 17 is adapted to be continuously oscillated by the motor'throughan arc of about 90 degrees, and is supported adjacent its ends, or at the, ends of each section, and preferably upon the exterior stoker side frames of the furnace by a bracket 18 bolted to the framework. The bracket 18 is provided with the bearings 19 in which said shaft is rotatably supported.

- Inasmuch as there are two sets of stoker grates to each section--a complete stoker consisting 'of any reasonable number of sectionswhich are alternately operated, there are provided two connecting rods 20, one connected to and actuating each set of stoker grates. Said rods 20 are mounted on opposite sides of each stoker section and extend through the front thereof as shown in Fig. 2'.

The rods 20 are indirectly actuated by the shaft 17 at timed intervals by the hereinafter described timing mechanism, there being one unit thereof connected with each rod 20 and positioned on each side of each stoker section, or in such a manner that they will not interfere with each other, so as to alternately I actuate said rods independently of each other,

otally mounted on the end of said pawl arm' there is a pawl block 22 provided with a pair of ratchet engaging fingers positioned adjacent to each other as indicated at 23 and 23 respectively. It will be notedthat the finger 23 is offset from or shorter than the finger 23. On the other side of the pawl arm, said block is provided with a stoker actuating finger 24.

The front of the furnace or stoker 10 is provided with a perforated lug 25 to whichis bolted a bracket 26 extending-forwardly and around the shaft 17 with a loose fit, and having a laterally extended hub portion 27 about which the timing wheels 28 and 29 are rotatably mounted. Said timing wheels are provided with a ratchet tooth periphery in position to be engaged by the pawl fingers 23 and 23 respectively. The position of the ratchet teeth about the periphery of each of said wheels divide it into 6 substantially equal sections offset from eachother by the ratchet teeth'as shown in Fig. 2. One of'the sections is deeply recessed as at 27 so as to permit the finger of the pawl, carried about the periphery of the wheel, to extend inwardly therefrom appreciably. The pawl fingers held in engagement with said wheel and caused to extend into the recessed section by reason of the weight 30 forming a part thereof and extending on the other Side of its pivotal mounting from thefingers. 'On the other hand there are provided the paw-ls 31 pivotally mounted at 32 on the bracket26, which are in position to engage the ratchet teeth and prevent a reverse movement of the wheels 28 and 29.

On the other side of the pawl arm 21 mounted about the shaft 17 and supported upon a suitable sleeve extending laterally from the pawl arm 21, there is a stoking arm hub 33 having a stoking arm 34 projecting downwardly therefrom and pivotally connected to the bifurcated head 35 of the rod 20 by the pin 36; Said stoking arm hub 33 is also provided with a recessed projection 37 in which a lever may be readily inserted oft e pawl block 22. The head 35 of the rod 20 is providedwith an enlargement adapted to seat in' a sealing plate 42 securedto the front of the furnace for the purpose of sealing the slotted opening through which the rod 20 operates in event forced draft is employed.

Operation.

In operation, assum-ingthat it is desired to actuate each respective set of stoker grates every 18 minutes and to complete the opera tion in 30 seconds of time for preventing their burning out, the main shaft is caused to oscillate every 30 seconds. Thus it would take 36 oscillations of the shaft'17 to impart action to the stoker grates, and one oscillation to complete the stoking action of 30 seconds. For such timing, .each of the timing wheels 28 and 29 are provided with 6 ratchet toothed sections substantially equally spaced about their periphery, one section being in the form of arecess of greater depth beyond the remaining recesses. v The oscillatory movement of the shaft imparts a like movement to the pawl arm 21 and pawl block 22. The pawl finger 23, being relatively longer than the reduced finger 23*, will engage the wheel 28, whereas the finger 23 will thereby be held out of engagement with the wheel'29. Thus upon each oscillation thereof the wheel 28 will be pushed or partially rotatedabout its hub 27 by the engaging action of the pawl finger 23. During the return movement of the pawl finger, said wheel will be held against reverse rotation by the pawl 31. It is obvious that it will take 6 oscillations of the shaft and pawl to rotate the wheel 28 one revolution, whereupon, by reason of the weight 30,lthe pawl will be caused to drop into'the recess of greater depth. As it drops into said recess, the pawl finger 23 will then engage the wheel 29 so thatthe next oscillatory movement of the pawl block will move both wheels one-sixth revolution. Thereupon when the pawl is returned itwill be withdrawn from the recess so that the finger 23 will again be out of engagement with the wheel 29. From the foregoing it will be observed that the Wheel-29 will be rotated one- .sixth revolution upon-each complete revolution of the wheel 28. Therefore it will take 36 oscillations of the shaft 17 at the rate of 30 seconds each, making a total of 18 min utes for the wheel 29 to make one complete revolution. At this point the deep recesses provided opposite 1y to such a position that the finger 24 will Cir engage the projection 41 on the stoking arm hub and force it forwardly for operating the stoker grates and elevating them to stoking position. This movement of the hub will cause the projection 38 and screw 39 to follow the pro ection 40 of the pawl arm in its regular oscillatory movement, and said proection 40 being directly actuated by the shaft will bear against and force the stoking arm hub in the reverse direction upon its return movement. As its return mover-pent is accomplished within 30 seconds from the beginning of the cycle, such return of the hub 33 will cause the stoker grates to be brought back to fuel supporting position within the 30 second period of time;

It will be observed from the foregoing that a convenient and economical timing mecha-- nism is employed for actuating the stoker grates, said mechanism being capable of similar employment for other purposes. The extent or length of time between each advancement or stoking grate movement is accomplished by varying the speed of the motor. The periodic actuation of the mechanism may be further widely extended or timed by varying the number of ratchet teeth in the timing wheels or by employing additional or less wheels. Thus if the wheel 29 were omitted in this instance, the actuation of the stoker grates would take effect every 3 minutes. If there were 7 teeth employed on the wheels instead of 6, the stokcr grates would be actuated every 24 minutes instead of 18 minutes. Thus the timing may be readily altered to an,indefini te extent.

The invention claimed is:

1. In a device of the character described, an oscillating shaft, a stoker grate, an arm mounted on the shaft and having connection with the grate, and means on the shaft cooperating with said arm to impart rocking movement to the arm for actuating said grate upon the completion of a predetermined number of oscillations of said shaft.

2. In combination with a stoker grate, of means for actuating said grate periodically including a shaft, means for imparting an oscillating movement to said shaft, an arm on the shaft having connection with the grate, and means on the shaft cooperating with the arm for imparting movement to the arm to actuate said grate upon a predetermined number of oscillations of the shaft.

3. The combination with a stoker grate, of means for actuating said grate periodically including an oscillating shaft, an arm on the.

shaft having connection with the grate, and means on the shaft cooperating with the arm to impart movement to the grate in one direction upon movement of the shaft in one direction after completing a predetermined number of oscillations, and means independent of the first means for moving said grate in an opposite direction upon the return movement of the shaft.

4. A device of the character described including an oscillating shaft, an arm mounted on the shaft for rocking movement, a StOkGl" grate, operative connection between said arm and sa1d grate, a palr of ratchets loosely mounted on the shaft, means whereby to move one ratchet a complete revolution upon a predetermined number of revolutions of the other ratchet, and means whereby to impart rocking movement to said arm during completion of one'revolution of the first ratchet upon a predetermined number of revolutions of the second ratchet.

5. Means for operating a stoker grate periodically including an oscillating shaft, an

arm mounted on the shaft for rocking movement and having connection with the grate,

a second arm on the shaft adjacent the first arm, ratchet members on the shaft rotatably independent of the movement of the shaft, adjacent pawl members carried by the second arm for en agement with said ratchets,

one ofsaid pawlis normally contacting one of said ratchets, means whereby one of said ratchets is caused to complete a predetermined number of revolutions during one revolution of the other ratchet, and cooperating means between said arms for imparting movement to the first arm for actuating the grate during the completion of one revolution of the last mentioned ratchet.

6. Means for operating a stoker grate pe riodically including an oscillating shaft, an arm mounted on the shaft for rockingmovement and having connection with the grate, a second arm on the shaft adjacent the first arm, ratchet members on the shaft rotatable independently of the movement of the shaft, adjacent pawl members carried by the second arm for engagement with said ratchets, one of said pawls normally contacting one of said ratchets, means whereby one of said ratchets is caused to complete a predetermined number of revolutions upon one revolution of the other ratchet, cooperating means between said arms for imparting movement to the first arm to move the grate in one direction during the completion of one revolution of the latter ratchet upon movement of the shaft in one direction, and means independent of the first means for moving said grate in an opposite dlirefction upon the return movement'of the s ia t.

7. In a device of the character described, an oscillating shaft, an arm mounted on the shaft for movement independent of the shaft, a stoker grate, operative connection between said arm and said grate, a pawl arm on the shaft to oscillate therewith, a pawl carried by the pawl arm adapted to cooperate with the first arm, and means carried by the shaft and 41- moses? cooperating with the pawl arm for causing said pawl to periodically actuate the first arm.

8. In a device of the character described, an oscillating shaft, an arm mounted on the shaft for movement independent of the shaft, a stoker grate, operative connection between said arm and said grate, ratchet members on the shaft rotatable independent thereof, and

means on the shaft to move therewith forming operative connection between the ratchet members and said arm for periodically iniparting movement to said arm.

9. In combination with a stoker grate, of means for periodicallyactuating said grate including an oscillating shaft, an arm on the shaft movable independently of the shaft, ratchet members on the shaft rotatable independently thereof, means on the shaft to move therewith forming operative connection between the ratchet members and said arm for periodically imparting movement to said arm, and means forming operative conneetion between said arm and stoker grate.

10. A device of the character described including an oscillating shaft, an arm mounted on the shaft for rocking movement independent of the movement of the shaft, a pair of ratchets mounted on the shaft, each formed with a single recess of greater depth than the remaining recesses, pivoted pawls supported upon said shaft with one of said pawls nor,- mally engaging one of said ratchets, means whereby the other pawl will engage the other ratchet uponthe first pawl reaching the recess of greater depth in the lirst ratchet, and means formin operative connection between the pawls and the rockable arm whereby to impart movement to said arm when the recesses of greater depth in both ratchets are moved to alignin position for simultaneous engagement by the pawls.

In witness whereof, I have hereunto aflixed my signature.

JOHN S. S. FULTON. 

